Percussion coal breaking mechanism



Aug. 26, 1952 5 c, ALLEN PERCUSSION COAL BREAKINQ MECHANISM 4 Sheets-Sheet 1 Filed July 21, 1950 Eldon 0. Allen INVENTOR.

BY QM and Aug. 26, 1952 Filed July 21 1950 E. c. ALLEN PERCUSSION COAL BREAKINQ MECHANISM 4 Sheets-Sheet 2 Eldon C. Allen JNVENTOR.

Aug. 26, 1952 E. c. ALLEN PERCUSSION COAL BREAKING MECHANISM Filed July 21, 1950 Fig. 4

lllllll 4 Sheets-Sheet 3 Eldon C. Allen INVENTOR.

26, 1952 c ALLEN 2,608,400

PERCUSSION COAL BREAKING MECHANISM Filed July 21, 1950 4 Sheets-Sheet 4 A a /777\ Fig.7

G 33 4 a/ as I 7 as o 0 2 o O o o v v 6,4 63 I I i 60 Eldon C. Allen 5.? INVENTOR.

BY MM fiM Patented Aug. 26, 1952 UNITED STATES PATENT OFFICE 2,608,400 PERCUSSION COAL BREAKING MECHANISM I EldonC. Allen, Harrisburgxlll.

Application July 21, 1950, S.cria1,No.,1YZ5,1,5!Z"

6 Claims.

My invention relates to improvements in percussion coal-breaking mechanism, for coal undercutting mining machines especially, although not necessarily.

The primary object of my invention is to provide in a coal mining machine of the type including a forwardly travelling and swingable cutter bar, percussion mechanism for impacting the coal with sharp powerful blows to break down and disrupt the coal at opposite sides. of the cutterbar;

Another object is to provide percussion mechanismfor the purpose set forth which is automatically operated by comparatively low fluid pressure to impactthecoal with sufficient force tobreak the coal down.

Another object'is to provide in such mechanism for automatic operation thereofunder control of swinging movement of the cutterbar."

Still another object is to provide percussion mechanism. for the above purposes which will not interfere with forward travel, nor swinging, of: the cutter bar;

Still another object is to provide such mechanism which is simple in construction, comparatively inexpensive to install, service and manufacture, and is substantially fool-proof.

Other and subordinate objects within the purviewof my invention, together with the precise; nature, of my improvements, will be readily understood when the succeeding description and claims are read, with reference to the: drawings accompanying and forming: part, of; this specification.

In. said drawings;

Figure 1, is a fragmentary view in side elevation, partly broken away and shown in section,

ofmy improved percussion mechanism embodied ina coal miningmachine of the type: specified; Figure 2 is a fragmentary view in side elevae tion, drawnto a: larger scale, of the front end of the cutter bar and one of, the pistons, or

rams;

Figure 3 is a view in longitudinal section taken,

trating the parts of} the pressure discharge means positioned for" discharge of pressure by said means.

Referring to the drawing by numerals, my improved percussion coal breaking mechanism has been shown; therein embodied in a usual type of mining machine, shown fragmentarily and conventionally, as suflicient for the present purpose, and which embodies a mechanism housing I on a skid base 2 for-movement along the floor 3 of a, mine in a manner which will be understood in the art to feed a front, forwardly extending cutter bar" 4 into a vein of coal. Thecutter'bar- 4 includes-apair of later-- ally spaced side frames 5 suitably secured to gether, in a manner not shown, and is pivotally unounted at its rear end, by a transverse rock shaft 6, in the upper'front portion of the housing I to incline downwardly and forwardly out of a slot" 1 in said housing for vertical swinging of saidbar on said shaft 6. The cutter 'bar 4 carries the usual, well understood, endless cutter chain 8 running" around the front end of said bar with cutter teeth 9- thereon and which is driven bymeans, not shown, counterclockwise as viewed in- Figure 1, to undercut a vertical slot Hlin the coal ll. During undercutting, by the cutter chain 8, the cutter bar 4 swings upwardly and downwardly intermittently due to tendency ofthefront end of said bar to climb upwardly in the coal and because of operation of the cutterteeth 9 against the coal, all as will be understood in the art.

According to my invention, a pair of opposed pistons, or rams, 12-, I3 are mounted in the front end of, the cutter bar at opposite sides thereof to slide outwardly and inwardly of said bar laterally thereof in a hollow cylinder [4 extending transversely through said frames 5' and suitably fixed by welding IS in openings H5 in said frames 5. The'pistons I2,. I3 are axially aligned and normally spaced apart. An annular, internal central shoulder IT in the cylinder M limits inward sliding of the pistons I2, 13.

Spring tension means connectssaid pistons l2, l3 to slide the sameinwardly into the inward limit ofmovementthereof, in which said pistons I2, l3 seat against opposite sides ofthe shoulder I! in spaced, apart relation and project slightly outwardly of opposite sides of the cutter bar 4. The springtension means comprises an axial bolt [8 threaded inthe piston l3 and extending into an axial bore I 9 in the piston I2, and a coil spring surrounding said bolt I8 in said bore I9 between the head I8 of said bolt and the outer end of an axial hollow stem I2 on the inner end of the piston I2 provided for extending the bore I9 to accommodate a spring of sufficient length when expanded to hold said pistons I2, I3 retracted against the shoulder IT. A threaded plug I9 in the outer end of the piston I2 closes the outer end of the bore I9. An axial well 23 in the inner end of the piston I3 accommodates the stem 22 to permit said pistons I2, I3 to seat against the shoulder I1 in close-together, spaced apart relation.

Stop means for limiting outward sliding or projection of the pistons I2, I3 is provided, as follows: Circumferentially spaced bolts 24 in said pistons I2, I3 slidably extend through the inner confronting ends of said pistons into circumferentially spaced recesses 25 in both said pistons. End nuts 26 on the bolts 24 working in said recesses 25 and adapted to engage the bottoms of said recesses coact with said bottoms to limit outward sliding of said pistons I2, I3. Screw plugs 21 in the outer ends of the pistons I2, I3 close the outer ends of the recesses 25.

The pistons I2, I3 are slid, or projected, outwardly under the action of pressure discharge means now to be described.

A longitudinally extending hollow cylinder 30 in the cutter bar 4, between the frames 5, is threaded at its front end into a radial pressure discharge neck M on the cylinder I4, said neck opening into the space between the pistons I2, I3. The front end of said cylinder 30 is threaded against an annular valve seat 32 in said neck 3| for seating a, pressure discharge control valve, presently described in detail. A cylindrical cap section 33 is threaded onto the rear end of said cylinder 33 with a follower piston 34 working therein.

The follower piston 34 is backed by a coil spring 35 in the cap section 33 and normally seated thereby against a shoulder 35-formed by the rear end of said cylinder 30. A valve stem 3! is carried in the cylinder 35 and cap section 33 by the follower piston 54 and is endwise slidable in an axial bore 38 in said follower piston 34 with a conical pressure discharge control valve 39 on the front end of said stem for seating in the beforementioned valve seat 32 to close the discharge neck 3|.

A coil spring 40 on the valve stem 3! bearing against the front face of the follower piston 34 and against a collar 4I, secured on said stem by a pin 42, urges said stem forwardly in the follower piston 34 to seat said valve 35 when said follower piston 34 is in its described normal position, said spring tensioning the valve stem 3! against rearward movement in said follower piston 34.

A coil spring 43 on the valve stem 31, between the rear face of the follower piston 34 and a nut 44 on the rear end of said stem 31, yieldingly opposes rearward movement of the follower piston 34 from normal position relative to said stem 3! and for a purpose presently seen. A bracket 45 mounts the cylinder 35 to said cutter bar 40.

As will presently more clearly appear, the cylinder 3B and the cap section 33 provide fluid pressure chambers 45, 41, respectively, in front of and in the rear of the follower piston 34.

A spring loaded, forwardly opening by-pass valve 58 in the follower piston 34, normally closes a by-pass port 59 in the follower piston 34 and opens said port 49 under fluid pressure in the pressure chamber 45 to by-pass pressure from chamber 4! to chamber 55.

A nipple 50 in the rear end of the cap section 33 provides for admitting fluid under pressure into the pressure chamber 4! in the rear of the follower piston 34 and for discharging fluid under pressure from said chamber 41 all for a purpose presently apparent. An air inlet nipple 52 on the rear end portion of the cylinder 38 provides for feeding fluid under pressure into the pressure chamber 56 forwardly "of the follower piston 34 for a purpose which will also presently appear.

A master fluid control valve 55 is suitably secured by bolts 55 in the housing I with a rotary valve core 5! having a diametrical port 58, a radial branch port 59 extending from said port 58, and a peripheral exhaust port 60 adapted to discharge outside said valve. A fluid pressure supply line 6i with a suitable cut-off valve 62 therein extends from a source of fluid under pressure, not shown, to said valve 55. A fluid pressure feed and'discharge line 64, in part flexible, extends from said valve 55 to the beforementioned nipple 50. A fluid pressure feed line 65, also in part flexible, extends from said valve 55 to the inlet nipple 52 for the pressure chamber The valve core 57 is rotatable for control purposes upon upward and downward swinging of the cutter bar 4 by valve operating mechanism described in the following. A crank arm I0 depends from one end of the rock shaft 6 and is loose on said shaft. A hand leverv II formed on said crank arm Iii with the usual detent dog I2 thereon for engagement with a toothed sector 73 fast on the shaft 5 provides for locking said crank arm I8 to said shaft 6 for swinging by vertical swing-ing of the cutter bar 4, said hand lever providing for variable adjustment of said crank arm I0 angularly on said shaft 6 for a purpose to be explained.

Ihe crank arm III is connected by a pin I4 and slot "I5 to one end of a toothed'rack bar It horizontally slidable endwise in guides 11 suitably bolted in the housing I, as at "I5. The rack bar I5 meshes with a gear pinion 19, keyed, as at '80, to a shaft 8i journaled in the housing I and having suitably fixed thereon a cam toothed wheel 82. As will be seen, by swinging of the crank arm 75 in opposite directions, endwise sliding movement is imparted to the rack bar I6 to rotate the cam toothed wheel 82.

A roller 83 on one end of a bellcrank 84, pivoted as at 85 in the housing I, rides the cam toothed wheel 82, said bellcrank 84 being tensioned by a suitably connected coil spring 86 to hold said roller against said wheel 82 whereby said bellcrank 84 is rocked from a normal position by the teeth of the toothed wheel 83 and returned to normal position by said spring 86. A link 81 is pivoted at one end, as at 88, to the other end of the bellcrank 84 with its other end pivoted, as at 89, to a crank arm 90 fixed on an axial stud 9! on the valve core 5?, and whereby'rocking of the bellcrank 84 out of and into normal position rotates said core 5i out of and back into normal position.

Referring now to the operation of my improved mechanism, with the roller 83 riding the cam toothed wheel between the teeth of said wheel, the bellcrank 84 is held by the coil spring 86 in its normal position, shown in Figure l, and thereby holds the valve core 5? in its normal position,

also shown in Figure 1. In the normal position of' the-eore 51, thep'or-t's 58', 5 9" communicate the fluid pressure supply line- 6t with the fluid pres sure feed and discharge line: 6'4 sothat, valve '62 being open, fluid under pressure is fed into the pressure chamber-4 slowly through a restricted port 5! in nipple 56. When the fluid pressure in the chamber 41'- buildsup to line pressure, it opens the by-pass valve 4811110 admitufluid from chamber 4'! into chamber 45 :until; the pressure in said chambers 41,: 46 is equalized, the fluid pressure chamber 4fi'then coacting with coil spring in holding the pressure discharge controlvalve iisseated.

When the cutter bar 4 swings, up or down, sufficiently to cause endwise movement of the rack bar 16 and consequent rotation of the cam toothed wheel 81 to the extent that the roller 83 rides onto a tooth of said wheel, the bellcrank 84 is swung from normal position in opposition to the coil spring 86 to cause rotation of the valve core 5'! from its normal position, clockwise as viewed in Figure l, untilthe branch port 59 and the diametrical port 58 communicate the fluid pressure supply line 6| with the fluid pressure feed line 65 and also communicate the exhaust port 60 with the fluid pressure feed and discharge line 64, all as shown in Figure '7.

When the valve core 51 is rotated from normal position, as described in the foregoing, fluid under pressure is discharged from chamber 4! slowly through port El and line pressure is admitted to the chamber 48 so that the piston follower 34 is moved rearwardly under the fluid pressure in the chamber 46 and along the valve stem 3'! in opposition to the coil springs 35 and 43, thus disabling coil spring 40, all while the fluid pressure discharge valve 39 is held to its seat by pressure in said chamber 46. When the follower piston 34 has moved back sufliciently to overcome the fluid pressure against the fluid pressure discharge control valve 39, said valve is suddenly opened, as shown in Figure 8, and coil spring 43 then expands to slide the valve stem 31 rearwardly in the follower piston 34 until coil spring 40 and coil spring 43 balance said stem in said follower piston.

As the fluid pressure discharge valve 39 is opened, a burst of fluid under pressure is discharged from chamber 46 into the space between the pistons I2, I3 to slidably project said pistons outwardly and impact the same against the coal II at opposite sides of the cutter bar 4 to break and disrupt the coal. The fluid pressure then discharges slowly around said pistons 12, I3 to atmosphere and the coil spring returns the pistons I2, 13 into their limit of movement inwardly of the cylinder l4. Back pressure release ports 92 are provided in the bottoms of the recesses for a purpose which will be apparent. As the fluid pressure discharges from the chamber 46, the coil spring returns the follower piston 34 against the shoulder 36, said piston 34 moving the valve stem 31 forwardly to seat the fluid pressure discharge control valve 39 and compress the coil spring so as to tension said valve against the seat 32 for closing the neck 3!.

As soon as the roller 83 rides off a tooth of the toothed wheel 82, the bellcrank 84 and valve core 31 are returned to normal position by the fed to chamber 4! to be by-passed through bycoil spring 86 and fluid under pressure is again pass port 49 into the chamber 46 in the manner already described, thereby completing a cycle of operation of the percussion mechanism. The percussion mechanism completes a cycle of operation; each time: the roller, 83 rides; onto an'clmfia Manifestly; the: invention as described is; S1151? ceptible of modification, without departingrfroma the inventive concept, and right as herein reserved to such modifications as fall within the scope of the appended claims.

Having described the invention, what claimed as new is: V

1. In a coal mining machine, the combination with a pivotal coal cutter bar swingable on its pivot, of percussion mechanism for breaking coal at opposite sides of said bar comprising a pair of axially aligned spaced apart pistons slidably mounted on said bar for projection outwardly of said bar at opposite sides ofthe same to impact the coal, means to intermittently introduce fluid under pressure into the space between said pistons to project said pistons intermittently including a fluid controlled valve, and means to operate said valve by swinging movement of said bar settable to variably time operation of said valve relative to swinging of said bar.

2. In a coal mining machine, the combination with a pivoted coal cutter bar swingable on its pivot, of percussion mechanism for breaking coal at opposite sides of said bar comprising a pair of coaxial spaced apart pistons slidably mounted on said bar for projection outwardly of said bar at opposite sides thereof to impact the coal, and means to intermittently introduce fluid under pressure into said space to project said pistons intermittently controlled by swinging movement of said bar comprising a fluid pressure discharge cylinder carried by said bar, valve means in said cylinder for controlling the discharge of fluid opened by a predetermined fluid pressure in said cylinder, means to feed fluid under pressure into said cylinder including a normally closed fluid feed control valve, and operating connections between said bar and the fluid feed control valve for opening said valve by swinging of said bar.

3. The combination of claim 2 wherein said operating connections comprise a pivoted roller carrying lever operatively connected to said valve, a cam toothed wheel engaged by said roller for swinging said lever on its pivot, and wheel rotating devices operated by said bar upon swinging of said bar.

4. The combination of claim 2 wherein said operating connections comprise a pivoted roller carrying lever operatively connected to said valve, a cam toothed Wheel engaged by said roller for swinging said lever on its pivot, and rack and pinion devices for rotating said wheel operated by said bar upon swinging of said bar.

5. In a coal mining machine, the combination of a pivoted coal cutter bar swingable on its pivot, of percussion mechanism for breaking coal at opposite sides of said bar comprising a pair of coaxial spaced apart pistons slidably mounted on said bar for projection outwardly of said bar at opposite sides thereof to impact the coal, and

means to intermittently introduce fluid under pressure into said space to project said pistons intermittently comprising a fluid pressure discharge cylinder carried by said bar, a fluid pressure discharge control valve in said cylinder, a slidable follower in said cylinder in which said valve is slidable into closed position, spring means between said valve and follower normally closing said valve and disabled'by initial sliding of said follower, means operatively connecting said follower to said valve to open the valve upon sliding of said follower after disabling of said spring means by initial sliding of the follower, and means to feed fluid under pressure into said cylinder to slide said follower controlled by swinging of said bar. 7

6. In a coal mining machine in accordance with claim 5, said last named means comprising a fluid feed control valve, and operating connections between said bar and feed control valve.

ELDON C. ALLEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,148,495 Osgood Feb. 28, 1939 

